The width-to-thickness ratios of steel elements are automatically controlled and reported with steel elements reports according to Table D1.1.


Symbols

Fy = Specified minimum yield stress
Ry = Ratio of the expected yield stress to the specified minimum yield stress, Fy
Rt = Ratio of the expected tensile strength to the specified minimum tensile strength, Fu
Pa = Required axial strength using ASD load combinations, kips (N)
Pu = Required axial strength using LRFD load combinations, kips (N)
Py = Axial yield strength , kips (N)
Ca = Ratio of required strength to available axial yield strength
E= Modulus of elasticity of steel = 29,000 ksi (200 000 MPa)


Local buckling, when repeated like low-cycle fatigue caused by an earthquake, can cause very high localized stresses that can cause premature failure of an element intended to behave in a ductile manner. In order for horizontal structural system elements to achieve sufficient plastic deformation without local buckling under the effects of earthquakes, the width-thickness ratios of the compression elements must meet the conditions given in the Table D1.1.

The width-to-thickness ratios of steel elements are automatically controlled and reported with steel elements reports according to Table D1.1.